Ulcerative colitis and Crohn's disease are the major forms of chronic inflammatory bowel diseases (IBD) in humans. Intestinal bowel disease is an inappropriate immune response that occurs in genetically susceptible individuals as the result of a complex interaction among environmental factors, microbial factors and the intestinal immune system. It has been demonstrated that the excessive immune response to mucosal antigens inappropriately controlled by the normal counter-regulatory mechanisms leads to chronic intestinal inflammation.
Crohn's Disease is a chronic, relapsing inflammatory disease of the gastrointestinal tract, characterized by segmental transmural inflammation and granulomatous changes. Typical presentations include the discontinuous involvement of various portions of the gastrointestinal tract and the development of complications including strictures, abscesses or fistulas. Because its cause is unknown, medical management of Crohn's disease is largely empirical and is designed to reduce inflammation. Medical therapy includes corticosteroids, antibiotics, immunosuppressant drugs, and anti-TNFα agents. Due to the therapeutic failures and serious side effects of present therapies, alternatives are needed.
An important role in the pathogenesis of IBD is played by TGF-β1, a multifunctional cytokine capable of regulating the growth, differentiation, and function of immune and non-immune cells. A diminished ability to mount an efficient counter-regulatory TGF-β1 response to inflammatory stimuli is believed to be relevant in the pathogenesis of disease such as IBD. TGF-β1 acts as a potent negative regulator of mucosal inflammation and that the inhibition of its activity results in the development of colitis which shows immunomorphological similarities with Crohn's disease or ulcerative colitis.
In the inflamed intestine of patients with IBD there is marked over expression of Smad7 (a protein that serves as substrates for TGF-β1 receptors) and a reduction of Smad 3 phosphorylation, a crucial step in the TGF-β1 mediated signal transduction. Thus, in IBD, high levels of Smad7 may lead to a defective TGF-β1 signaling resulting in an over-expression of pro-inflammatory molecules genes and TGF-β1 does not exert its anti-inflammatory role.
Antisense oligodeoxynucleotide drugs are short chains of DNA nucleotides that inhibit protein translation by specifically binding to a small segment of messenger RNA (mRNA) responsible for driving the production of disease-causing proteins. The sequence of an antisense drug is designed to be complementary to its mRNA target such that, upon hybridization, the resulting double-stranded segment is recognized by the cell as abnormal and is destroyed, thereby preventing translation of the message into the protein product.
Antisense therapeutics, however, are typically administered parenterally which can lead to adverse reactions due to systemic effects. Such administration may also be unable to localize at the site of needed treatment. Therefore, there is a need for a topical-like application of antisense treatments for the treatment of IBD and related diseases using tablet based formulations.